Taylor–Aris Dispersion in Nanotubes: Analytical Solution, Effects of Slip and Surface Potential Landscape, and Measurement of the Slip Length

Taylor-Aris (T-A) dispersion of a solute in a flowing solvent is a fundamental phenomenon in most mass-transfer processes. Despite its significance and numerous applications in microreactors, colloidal transport in confined media, chromatographic separation, and transport in biological tissues, the effect of the slip length and the topology of surface potential landscapes on T-A dispersion in nanostructured channels has not been studied in detail. We propose a novel methodology for molecular dynamics (MD) simulation of T-A dispersion in such systems, derive an analytical expression for the dispersion coefficient in them, and report on the results of extensive MD simulations of the phenomenon in carbon nanotubes and hexagonal carbon nanochannels. By broadening the topology of the surface energy landscape, we vary the slip lengths, making it possible to distinguish between the effects of confinement, the topology of the energy landscape, and the slip length on the T-A dispersion coefficient. It is demonstrated that measuring the T-A dispersion coefficient in laminar flow is a straightforward and reliable approach for estimating the slip length in nanotubes and other nanostructured materials.